Regeneration and transformation protocols for 'Comet' red raspberry were optimized with the purpose of making the Agrobacterium-mediated gene transfer system efficient for this crop. Adventitious shoot regeneration from leaf discs was improved using explants 10 mm in diameter and transferring to fresh medium at the fourth week of incubation. Additions of liquid medium to solid medium during incubation decreased regeneration and attempts to release the suppressive influence of larger shoots on initials (apical dominance) did not succeed. The presence of claforan did not affect shoot regeneration, but inoculations with Agrobacterium and the presence of kanamycin decreased regeneration moderately or considerably, respectively. The threshold for kanamycin concentration for screening for kanamycin resistant transformed raspberry tissue was 30 to 40 mg l$ sp{-1}.$ The best co-incubation interval between wild-type Agrobacterium and 'Comet' leaf discs ranged from 2 days for highly virulent strains to 3 or more days for moderate to low virulent strains. Among several wild-type strains, C58 was chosen as the most appropriate partially because a disarmed form was commercially available for use as a non-oncogenic vector for transformation of red raspberry. / The binary plasmid pBI121 containing the marker genes NPTII and GUS encoding kanamycin resistance and $ beta$-glucuronidase activity, respectively, was successfully introduced into the Agrobacterium strain LBA4404, which is a disarmed C58 derivative. Transformation of 'Comet' red raspberry was apparently achieved by inoculating leaf disc explants with LBA4404 containing pBI121. The probable integration and expression of the foreign genes into the plant cells were confirmed by screening for kanamycin resistance, GUS assays and Southern blot analyses. This transformation system appears to be effective and may be useful in further studies on red raspberry for both introduction of genes for desirable agronomic traits and basic studies of gene expression.

An Agrobacterium-mediated transformation system of purple raspberry ‘Amethyst’ was established after a series of experiments that determined the effect of genotype, inoculum density, and co-cultivation time on transformation. In this study, a plant regeneration protocol was established for ‘Joan J’ and ‘Polana’ (the regeneration protocol of ‘Amethyst’ was previously developed). Agrobacterium-mediated transformation was conducted for all three cultivars. The minimum killing level of hygromycin B and kanamycin was determined. Inoculum density and co-cultivation time were optimized. Polymerase chain reaction (PCR) verified a successful transformation of ‘Amethyst’ with the frequency of 3.3 ~ 4.4 % when leaves were infected with Agrobacterium EHA105 at the cell density of OD600 0.3 and co-cultivated for 3 days in the medium with 25.0 mg∙l-1 kanamycin. Transgenic lines with the PtFIT gene were hydroponically grown under iron sufficiency or deficiency. The real-time quantitative PCR verified the gene expression in response to iron sufficiency and deficiency conditions.

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